The use of soil release agents in laundry products per se is known in the art.
Examples of laundry detergent compositions containing cellulose ether soil release agents are disclosed in U.S. Pat. Nos. 4,000,093, C. H. Nicol and M. E. Burns, issued Dec. 28, 1976; 4,100,094, M. E. Burns, issued July 11, 1978; and 4,564,463, Secemski et al., issued Jan. 14, 1986. Examples of laundry presoak compositions and rinse additive compositions containing cellulose ether soil release agents are disclosed in U.S. Pat. No. 4,136,038, H. J. Pracht and M. E., Burns, issued Jan. 23, 1979. Examples of laundry detergent compositions containing terephthalate ester/ethylene oxide copolymers are disclosed in U.S. Pat. NoS. 4,132,680, C. H. Nicol, issued Jan. 2, 1979; 4,116,885, Derstadt et al., issued Sept. 26, 1978; and 4,411,831, Robinson et al., issued Oct. 25, 1983.
U.S. Pat. No. 4,348,293, D. E. Clark et al., issued Sept. 7, 1982, discloses the use of a wide variety of water-soluble and water-dispersible coating materials to coat water-insoluble, water-permeable detergent pouches. U.S. Pat. No. 4,374,747, H. T. Tai, issued Feb. 22, 1983, discloses a variety of organic materials suitable for coating water-insoluble, water-permeable bleach pouches such that the coatings are removed by water in the temperature range of 35.degree.-70.degree.C. None of the coating materials disclosed in U.S. Pat. Nos. 4,348,293 and 4,374,747 are believed to be effective soil release agents.
U.S. Pat. No. 4,082,678, H. J. Pracht and L. F. Wong, issued Apr. 4, 1978, discloses a through-the-wash fabric conditioning article with an inner receptacle and an outer receptacle.
U.S. Pat. No. 4,532,063, T. G. Gueldensopf, issued July 30, 1985, discloses a fully dissolving bleach sheet comprising a bleaching compound and a sheet made from a water-soluble filmforming polymer, a solubilizer and a surfactant. This latter patent does not appear to disclose water-insoluble sheets having a coating of soil release agent.
U.S. Pat. No. 3,632,396, Zamora, issued Apr. 28, 1969, discloses substrates coated with a substantially solid, waxy, cationic or nonionic material and an outer coating of a fabric softener and, optionally, an unspecified soil release agent for use in an automatic rinse cycle of a washer or an automatic clothes dryer. U.S. pat. No. 4,238,531, Rudy et al., issued Dec. 9, 1980, discloses in its Examples 8 and 9 a soil release agent adjuvant plus a "distributing aid," polyethylene glycol (PEG) for an automatic clothes dryer.
In none of the above disclosures was there an indication of superior or synergistic soil release performance benefits in using any type of in-the-wash cleaning composition in combination with a substrate coated with a soil release polymer.